Mountain Weather Forecast

Weather Synopsis

Update: Fixed Timberline precipitation typo for tonight

Early this afternoon, relatively quiet weather is over the region with leftover clouds and scattered showers found along the west slopes of the Cascades from about I-90 and south to Mt Hood and a mix of sun and clouds elsewhere. Our region sits between strong upper level ridging offshore (around 140W) and long wave troughing that encompasses much of the continental US and Canada.  An upper level trough will slide down the backside of the upper level trough tonight and pass through our region on Saturday. This system will be relatively moisture-starved but it will accomplish 2 things; 1.) it will drop a few inches of low density snow in most areas and 2.) it will usher in much colder air into the region. 

As the trough drops south over the area during the day, a weak surface low will set up off the WA/OR border and help to bring additional lift and a little bit of Pacific moisture into the equation.  As winds turn more northerly and eventually easterly by the afternoon, we'll also get the added bonus of some upslope snow favoring the east slopes of the Cascades, especially for the terrain near and south of Hwy 2.  Expect light snow to develop during the day from about Stevens Pass and southward to Mt Hood with a few inches of snow expected through Saturday evening. Drier conditions will prevail further north. Temperatures will begin to drop during the day for most areas as cold arctic air from the interior spreads southward. Moderate ENE winds will begin to pick up Saturday afternoon as well. 

Showers should diminish Saturday night as the trough digs further down the coast.  Moderate to locally strong ENE winds will continue overnight. Snow showers will continue longest in the Mt Hood area. We are in for a dry and cold Sunday with brisk E-NE winds generally diminishing during the day.